The first self-consistent modeling of collisional water transport during late-stage planet formation

Autor(en)

Christoph Burger, Christoph M. Schäfer, Akos Bazso, Thomas I. Maindl

Abstrakt

The final phase of terrestrial planet formation, where planetary embryos and remaining planetesimals accrete into planets, is a dynamically stochastic process, marked by giant collisions among protoplanets and radial mixing of material over wide distances, where the origin and abundance of water is strongly tied to collisional transfer and loss processes, and of central importance for their habitability. Several approaches for treating collisions beyond (over-)simplified perfect inelastic merging have been developed in recent years, but none has been designed nor applied for modeling the collisional evolution and delivery of water to growing terrestrial planets, even though it is particularly susceptible to collisional transfer and erosion. To eventually close this gap we have successfully developed a new hybrid framework to directly combine long-term N-body integrations with Smooth Particle Hydrodynamics (SPH) simulations of individual collision events, which allows us to self-consistently model collisional water transport on a system-wide scale for the first time. This includes full treatment off requent hit-and-run events, where not only water losses but also transfer between the colliding bodies can be crucial. In a solar-system-like setting as the first application, our simulations include varying gas giant architectures, and a bi-modal initial distribution of embryos and smaller bodies, where we find that with a realistic collision treatment final water contents are reduced by a factor of 2 or more. Our results show that water delivery is dominated by very few decisive accretionary and frequently also hit-and-run encounters, with embryo-sized or even larger impactors, and only rarely smaller bodies. Even though our model includes their collisional evolution, they seem to play only a minor (direct) role in water transport to potentially habitable planets. Beyond this first application and exciting results, we believe that this methodology offers a solid basis for including further decisive physical processes, towards a deeper understanding of water transport to terrestrial planets throughout the galaxy.

Organisation(en)

Institut für Astrophysik

Seiten

70

Publikationsdatum

08-2019

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/3e45c515-6df1-40b0-a4e2-d5d32b1a43f9